An investigation as to why some patients with Sjogren-Larsson Syndrome (SLS) have severe symptoms and some have mild symptoms. SLS is a genetic disorder of fatty alcohol metabolism due to a faulty gene that is responsible for the metabolism of fatty aldehydes and fatty alcohol. Symptoms resulting form this syndrome are scaling skin, developmental delay, spasticity, mental retardation, and inability to walk. Patients survive well into adulthood. The accumulation of the unmetabolized fat is thought to cause the symptoms. The purpose of this study is to determine whether and to what extent the symptoms of SLS are effected by variation in the metabolism of fatty alcohol and in the dietary intake of this fat. This study will consist of two parts. Patients with SLS may be enrolled in both parts and normal volunteers will be enrolled only in the second part. SLS patients will be admitted to the General Clinical Research Center for three days during which they will be given a physical to determine the makeup of the body. Photographs will be taken of the skin problems. The eyes will be examined for glistening, white spots. A brain MRI (magnetic resonance imaging) will be done to determine brain disease. A skin biopsy will be performed. Blood samples will be taken to measure fatty alcohol accumulation. Instructions will be given on how to record a dietary history at home. Types and amounts of food will be recorded. In part 2, adult SLS and normal subjects will be included. It will take three days and subjects will be given a type of fatty alcohol to drink. After an overnight fast, fluids and sugar will be given intravenously for eight hours. Fasting will continue for eight more hours. Eleven blood samples will be taken over a 48 hour period.